Motor cortex stimulation in deafferentation facial pain

Objective — to demonstrate the results of treatment of poorly controlled deafferentation facial pain using motor cortex stimulation and to review the relevant literature. Material and methods. The study included 8 patients (3 males and 5 females) with deafferentation facial pain who were implanted with a system of constant motor cortex stimulation at the Illinois University in Chicago in 2004―2016 and Novosibirsk Federal Center of Neurosurgery in 2017. The patients’ age ranged from 37 to 81 years (mean age, 57.5 years). Scale-based assessment of the pain severity was performed at admission to hospital, at discharge, and during follow-up. The visual analogue pain scale, Barrow Neurological Institute pain scale (BNIPS), and McLaughlin scale were used. Results. Immediately after surgery, a significant improvement in the form of pain reduction by 80―100% occurred in 4 patients. The pain intensity at discharge from the hospital decreased by 55%, on average. During the follow-up period, the efficacy of motor cortex stimulation was assessed (McLaughlin scale) as very good by 3 of the 8 patients, as good by 4 patients, and as unsatisfactory by 1 patient. Conclusion. Our findings and recent studies have demonstrated that motor cortex stimulation is one of the treatment options for deafferentation facial pain. Even a slight decrease in the intensity of excruciating and debilitating pain (assessed by patients as a good effect) gives grounds for application of the procedure. Further research is needed to define more precise criteria for selecting patients for this treatment and to increase the efficacy of stimulation.